1. Field of the Invention
The present invention relates generally to the field of semiconductor packaging, and more particularly to a wafer level package (WLP) having fine-pitch redistribution layer (RDL) and a method for manufacturing the same.
2. Description of the Prior Art
As known in the art, fan-out wafer-level packaging is a packaging process in which contacts of a semiconductor die are redistributed over a larger area through a redistribution layer (RDL).
The RDL is typically defined by the addition of metal and dielectric layers onto the surface of the wafer to re-route the I/O layout into a looser pitch footprint. Such redistribution requires thin film polymers such as BCB, PI or other organic polymers and metallization such as Al or Cu to reroute the peripheral pads to an area array configuration.
In wafer level packaging, the wafer and the dies mounted on the wafer are typically covered with a relatively thick layer of the molding compound. The thick layer of the molding compound results in increased warping of the packaging due to coefficient of thermal expansion (CTE) mismatch, and the thickness of the packaging. It is known that wafer warpage continues to be a concern.
Warpage can prevent successful assembly of a die-to-wafer stack because of the inability to maintain the coupling of the die and wafer. Warpage issue is serious especially in a large sized wafer, and has raised an obstacle to a wafer level semiconductor packaging process that requires fine-pitch RDL process. Therefore, there remains a need in the art for an improved method of manufacturing wafer level packages.